1. Field of the Invention
The present invention relates to a diagnostic x-ray system and a method thereof used to practice perfusion using CT images of, for example, coronary arteries and brain portions of a test subject which are obtained by computed tomography, and X-ray images obtained by the diagnostic x-ray system, in order to diagnose and care the test subject.
2. Description of the Related Art
Perfusion using a CT device and a diagnostic x-ray system are very significant to diagnose a test subject such as a human body and to identify therapy effects. For perfusion, there are a method for performing an analysis by using a CT image obtained by a CT device, and a method for performing an analysis by using an X-ray image obtained by a diagnostic x-ray system are overlapped each other.
Meanwhile, for a medical operation for myocardial ischemia, there is a manipulation in which a catheter is inserted up to a narrowed portion and a balloon attached to the catheter is spread to enhance the narrowed portion. For a medical operation for a cerebral aneurysm, there is a manipulation in which a catheter is inserted up to a cerebral aneurysm and a coil is projected from a tip end of the catheter, to stuff the cerebral aneurysm with the coil. Medical operations using a catheter are called interventions, and recently attract much interest as a medical care which requires less invasion than an surgical cure.
To check perfusion in a test object, use of CT images obtained by a CT device or MRI images obtained by a MRI device before a medical operation of the intervention is most preferred as a modality. In the intervention, there is no other way but using X-ray images obtained by a diagnostic x-ray system when checking a therapeutic process or when finally checking a medical care.
A technique relevant to perfusion of a test subject is disclosed in, for example, Jpn. Pat. Appln. KOKAI Publication No. 2008-136800. This publication discloses that an index representing an inflow state of blood and an index representing an outflow state of blood are calculated about a local coronary muscle such as a myocardium of a test subject.
To know improvements in inflow and outflow states of blood into and from a coronary artery of a test subject between before and after a medical care, indices representing inflow and outflow states of blood need be compared. To compare the indices, perfusion need be practiced with use of a diagnostic x-ray system both before and after a medical care. To practice perfusion, which has already analyzed by a CZT device, again with use of a diagnostic x-ray system is to expose the test subject to X-rays for a clinically less worthy purpose.
The invention has an object of providing a diagnostic x-ray system and a method thereof capable of comparing perfusion before and after a medical cure without increasing an exposure dose.